Africa to the European powers which have been
establishing themselves on the coasts. No one who lives within thirty
miles of the sea nearly all the way south from Cape Guardafui to
Zululand can hope to escape it. It is frequent all round the great
Nyanza lakes, and particularly severe in the valley of the Nile from the
lakes downward to Khartoum. It prevails through the comparatively low
country which lies along the Congo and the chief tributaries of that
great stream. It hangs like a death-cloud over the valley of the
Zambesi, and is found up to a height of 3000 or 4000 feet, sometimes
even higher, in Nyassaland and the lower parts of the British
territories that stretch to Lake Tanganyika. The Administrator of German
East Africa has lately declared that there is not a square mile of that
vast region that can be deemed free from it. Even along the generally
arid shores of Damaraland there are spots where it is to be feared. But
Cape Colony and Natal and the Orange Free State are almost exempt from
it. So, too, are all the higher parts of the Transvaal, of Bechuanaland,
of Matabililand, and of Mashonaland. Roughly speaking, one may say that
the upper boundary line of malarial fevers in these countries is about
4500 feet above the sea, and where fevers occur at a height above 3000
feet they are seldom of a virulent type. Thus, while the lower parts of
the Transvaal between the Quathlamba Mountains and the sea are terribly
unhealthy, while the Portuguese country behind Delagoa Bay and Beira as
far as the foot of the hills is equally dangerous,--Beira itself has the
benefit of a strong sea-breeze,--by far the larger part of the recently
occupied British territories north and west of the Transvaal is
practically safe. It is, of course, proper to take certain precautions,
to avoid chills and the copious use of alcohol and it is specially
important to observe such precautions during and immediately after the
wet season, when the sun is raising vapours from the moist soil, when
new vegetation has sprung up, and when the long grass which has grown
during the first rains is rotting under the later rains. Places which
are quite healthful in the dry weather, such as Gaberones and the rest
of the upper valley of the rivers Notwani and Limpopo in eastern
Bechuanaland, then become dangerous, because they lie on the banks of
streams which inundate the lower grounds. Much depends on the local
circumstances of each spot. To illustrate th